title: Quadrature phase interferometer for high resolution force spectroscopy.
abstract: In this article, we present a deflection measurement setup for Atomic Force Microscopy (AFM). It is based on a quadrature phase differential interferometer: we measure the optical path difference between a laser beam reflecting above the cantilever tip and a reference beam reflecting on the static base of the sensor. A design with very low environmental susceptibility and another allowing calibrated measurements on a wide spectral range are described. Both enable a very high resolution (down to 2.5×10(-15) m/√Hz), illustrated by thermal noise measurements on AFM cantilevers. They present an excellent long-term stability and a constant sensitivity independent of the optical phase of the interferometer. A quick review shows that our precision is equaling or out-performing the best results reported in the literature, but for a much larger deflection range, up to a few μm.
authors.affiliation: Laboratoire de physique, Université de Lyon, ENS Lyon, CNRS, Lyon 69364, France.
authors.forename: Pierdomenico
authors.initials: P
authors.lastname: Paolino
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Aguilar Sandoval
authors.forename: Ludovic
authors.initials: L
authors.lastname: Bellon